The present invention relates to a new and distinct cultivar of hybrid Baptisia plant, botanically known as Baptisia ‘Indigo Spires’ and will be referred to hereafter by its cultivar name, ‘Indigo Spires’. The new cultivar represents a new false indigo, a hardy herbaceous perennial grown for landscape and cut flower use.
The new invention arose from a long term breeding program at a nursery in Waseca, Minn. and continued at a wholesale perennial nursery in Zeeland, Mich. with the specific intention of improving garden worthiness of perennial False Indigo plants with a wider variety of flower colors and improved garden habit.
Baptisia ‘Indigo Spires’ was a selection of a specific unreleased but unidentified proprietary seed parent of Baptisia minor and the male or pollen parent was an unknown Baptisia from an open pollinated isolation block selection consisting of proprietary complex hybrids. Also in the isolation block were advanced hybrids of Baptisia minor and sphaerocarpa. 
The plant was originally selected in June of 2008 at the isolation block in Waseca, Minn., USA by the inventor. Evaluations were continued with final evaluations conducted in 2012 at a wholesale perennial nursery in Zeeland, Mich. The exact identity of the female and male parents is not known but both were from proprietary unreleased and non-patented hybrid plants containing traits of both Baptisia minor and Baptisia sphaerocarpa. Asexual propagation by cuttings was initially propagated in spring 2008 at a wholesale perennial nursery in Waseca, Minn. The results of asexual propagation are that the new plant is stable and retains its true characteristics though successive generations of asexual propagation. Propagation method for asexually reproducing plants is primarily stem cuttings. Sterile plant tissue culture can also be used for asexual propagation.
Compared to Baptisia ‘Midnight’ U.S. Plant Pat. No. 20,432, the new plant is shorter and more compact and has darker blue flowers. Baptisia ‘Indigo Spires’ also has darker blue flowers than ‘Twilight’ U.S. Plant Pat. No. 19,011 and much darker and more blue flowers than Baptisia ‘Purple Smoke’ (not patented).
Baptisia ‘Indigo Spires’ differs from all cultivars known to the inventor in the following combined traits:                1. Upright vase-shaped habit with thick upright stems;        2. Many large, dark indigo-colored flowers on well-branched stems held well above the foliage in the spring;        3. Dense medium to dark green foliage.        